Sister chromatid exchange (SCE) in Greenlandic Eskimos. Dose-response relationship between SCE and seal diet, smoking, and blood cadmium and mercury concentrations.

The mutagenicity of the chromosomes of the peripheral lymphocytes of 147 Greenlandic Eskimos living in the district of Angmagssalik, Greenland, and in Denmark, was evaluated by means of the sister chromatid exchange (SCE) test. Thirty cells from each person were examined. The purpose of the investigation was to determine if there was any relationship between mutagenic activity and diet, and hence the elements selenium, cadmium, mercury and lead. The probands were divided into three groups according to their intake of seal meat or industrially prepared food: group 1, those eating seal at least six times per week; group 2, two to five times per week; and group 3 once each week or not at all. The statistical analysis was performed by means of multiple linear regression analyses, with diet, living district, sex, age, tobacco smoking, and blood lead and mercury concentrations as variables. Forty-eight percent of the variation in SCE could be explained by differences in diet, living district, age, and tobacco consumption. Groups 1 and 2 had a 1.7 and 0.65 times higher SCE/cell, respectively, than group 3. For every additional 10 years of age of the probands, the SCE/cell increased by 0.4, and for every 10 g of tobacco smoked per day the SCE/cell was 0.7 higher compared to non-smokers. When priority was given to blood Hg concentration in the calculation, 16.3% of the total variation in SCE/cell could be explained. An increase in the blood Hg concentration of 10 micrograms l-1 corresponded to an increase of 0.3 SCE/cell. In 92 individuals blood Se and Cd concentrations were also analysed. The variables, tobacco smoking, diet, living district and Cd explained 53% of the total variation in SCE. Giving priority to the blood Hg and Cd concentrations, explained 21.4% of the total variation in SCE/cell. An increase of 10 micrograms l-1 in blood Cd and Hg corresponded to an increase in SCE/cell of 0.7 and 0.2, respectively. No influence on the SCE/cell could be attributed to the blood Pb and Se concentrations. Evaluated by the SCE test, seal diet, smoking, living district and blood Hg and Cd concentrations all contribute to mutagenicity in Greenlandic Eskimos, with seal diet as the most important of the factors examined.